Question: Simplify the following expression: $2\sqrt{18}$.
First, try to factor a perfect square out of the radical. $= 2\sqrt{18}$ $= 2\sqrt{9 \cdot 2}$ Separate the radical and simplify. $= 2\sqrt{9} \cdot \sqrt{2}$ $= 2 \cdot 3 \cdot \sqrt{2}$ $= 6\sqrt{2}$